1. Field of the Invention
The present invention relates to an apparatus for evaluating blood platelet functionality. More specifically, the invention relates to an improved multicell cartridge for use in evaluating blood platelet functionality and method for using the same.
2. Description of the Prior Art
It has been observed that blood platelets play a significant role in the clotting or coagulation of whole blood. When platelets are activated, they shorten the clotting time of the blood. This shortening is related to the initial status of the platelets and platelet disfunction is considered a leading cause of post-surgical bleeding following cardiopulmonary bypass surgery.
Blood platelet functionality is conventionally determined by mixing blood and a clot promoting reagent such as kaolin in a buffer solution. This is done in a series of test cells incorporated in a test cartridge. After adding the clotting reagent, the blood/kaolin solution in each cell is agitated to activate the platelets to promote clotting. The degree of agitation of the blood sample in each cell differs one from the other. As described in U.S. Pat. No. 5,314,826, the clotting time is proportional to the degree of agitation. By comparing clotting times of aliquots of the blood as a function of degree of agitation, the blood platelet functionality can be determined. This process and the apparatus for carrying it out are disclosed in detail in U.S. Pat. Nos. 4,599,219 and 5,314,826. Where necessary for a further understanding of the present invention, the disclosures in these two patents are incorporated by reference herein.
Chemical platelet activators or reagents are well-known in the art. One such activator, 1-O-alkyl-2-acetyl-sn-glyceryl-3-phosphorylcholine, a biologically active phospholipid, is disclosed in Demopoulos, et al., J. Biol. Chem., 1979; 254:9355-8. This platelet activator or reagent, often referred to as a platelet activating factor, enhances the ability of active platelets to effectively participate in the blood clotting reaction and thereby shorten the clotting time of the blood. If the platelets are inactive or not functioning normally, the activator will have a lessened or no effect on the clotting time.